Method and system for lighting control and monitoring

ABSTRACT

Embodiments of the present invention are directed to control of lighting systems at individual-light-fixture, local, regional, and larger-geographical-area levels. One embodiment of the present invention comprises a hierarchical lighting-control system including an automated network-control center that may control up to many millions of individual lighting fixtures and lighting elements, regional routers interconnected to the network-control center or network-control centers by public communications networks, each of which controls hundreds to thousands of individual light fixtures, and light-management units, interconnected to regional routers by radio-frequency communications and/or power-line communications, each of which controls components within a lighting fixture, including lighting elements, LED-luminaire drivers, sensors, and other devices.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of patent application Ser.No. 12/719,681, filed Mar. 8, 2010.

TECHNICAL FIELD

The present invention is related to lighting systems, and, inparticular, to automated control systems for controlling and monitoringindividual lighting elements, lighting elements associated withindividual fixtures, and arbitrarily sized groups of lighting fixtureslocated across local, regional, and larger geographical areas,particularly LED-based lighting.

BACKGROUND OF THE INVENTION

Lighting systems for public roadways, thoroughfares, and facilities,private and commercial facilities, including industrial plants,office-building complexes, schools, universities, and other suchorganizations, and other public and private facilities account forenormous yearly expenditures of energy and financial resources,including expenditures for lighting-equipment acquisition, operation,maintenance, and administration. Because of rising energy costs, fallingtax-generated funding for municipalities, local governments and stategovernments, and because of cost constraints associated with a varietyof different enterprises and organizations, expenditures related toacquiring, maintaining, servicing, operating, and administering lightingsystems are falling under increasing scrutiny. As a result, almost allorganizations and governmental agencies involved in acquiring,operating, maintaining, and administering lighting systems are seekingimproved methods and systems for control of lighting fixtures in orderto lower administrative, maintenance, and operating costs.

SUMMARY OF THE INVENTION

Embodiments of the present invention are directed to control of lightingsystems at individual-light-fixture, local, regional, andlarger-geographical-area levels. One embodiment of the present inventioncomprises a hierarchical lighting-control system including an automatednetwork-control center that may control up to many millions ofindividual lighting fixtures and lighting elements, regional routersinterconnected to the network-control center or network-control centersby public communications networks, each of which controls hundreds tothousands of individual light fixtures, and light-management units,interconnected to regional routers by radio-frequency communicationsand/or power-line communications, each of which controls componentswithin a lighting fixture, including lighting elements, LED-luminairedrivers, sensors, and other devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a portion of a traditional lighting system observedin parking lots, along thoroughfares and roadways, and within industrialsites, school facilities, and office-building complexes.

FIG. 2 shows a modestly sized industrial or commercial site withassociated lighting-fixture locations.

FIGS. 3A-B illustrates a conceptual approach to lighting-system controlthat represents one embodiment of the present invention.

FIG. 4 illustrates, using the same industrial-site layouts shown in FIG.2, groupings of individual lighting fixtures to facilitate automatedcontrol, as made possible by lighting-control systems that representembodiments of the present invention.

FIG. 5 illustrates a displayed schedule for automated control of thevarious groups of lighting fixtures shown in FIG. 4 according to certainembodiments of the present invention.

FIG. 6 provides a generalized architecture for the automatedhierarchical lighting-control system that represents one embodiment ofthe present invention.

FIG. 7 provides a block diagram for a radio-frequency-enabledlight-management unit according to one embodiment of the presentinvention.

FIG. 8 provides a block diagram for a stand-alone routing deviceaccording to one embodiment of the present invention.

FIG. 9 illustrates communications between routers,radio-frequency-enabled light-management units, and end-pointlight-management units according to one embodiment of the presentinvention.

FIG. 10 illustrates division of the 256 possible command codes into foursubsets, according to certain embodiments of the present invention.

FIG. 11 shows the type of data stored within each light-management unitaccording to certain embodiments of the present invention.

FIGS. 12A-B illustrate data managed by a router for all of the differentlight-management units or light-fixtures which the router managesaccording to certain embodiments of the present invention.

FIG. 13 shows various commands used in router-to-light-management-unitcommunications according to certain embodiments of the presentinvention.

FIGS. 14A-N show the data contents of the various commands and repliesdiscussed above with reference to FIG. 13.

FIGS. 15-18 provide flow-control diagrams for the control functionalitywith a light-management unit according to one embodiment of the presentinvention.

FIG. 19 provides a state-transition diagram for one router userinterface that represents one embodiment of the present invention.

FIG. 20 shows a block diagram for the RF-enabled LMU that represents oneembodiment of the present invention.

FIG. 21 provides additional description of the microprocessor componentof the RF-enabled LMU that represents one embodiment of the presentinvention.

FIG. 22 provides a circuit diagram for a portion of theoptocouple-isolation subcomponent of the RF-enabled LMU that representsone embodiment of the present invention.

FIG. 23 provides a circuit diagram for one embodiment of theswitched-relay component of the RF-enabled LMU that represents oneembodiment of the present invention.

FIG. 24 provides a circuit diagram for the internal-power-supplycomponent of the RF-enabled LMU that represents one embodiment of thepresent invention.

FIG. 25 provides a circuit diagram for the power-meter component of anRF-enabled LMU that represents one embodiment of the present invention.

FIG. 26 provides a circuit diagram for a circuit that interconnectsoutput from a sensor or monitor device to an interrupt-like input to themicroprocessor according to one embodiment of the present invention.

FIG. 27-29 illustrate characteristics of LED-based lighting elements.

FIG. 30 illustrates a LED-based street-light luminaire.

FIGS. 31-33 illustrate one type of constant-output-current LED lampdriver.

FIG. 34 illustrates an RF-enabled LMU/LED-based-luminaire-driver modulethat represents one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

There are many different types of lighting fixtures, lighting elements,or luminaires, and lighting applications. FIG. 1 illustrates a portionof a traditional lighting system observed in parking lots, alongthoroughfares and roadways, and within industrial sites, schoolfacilities, and office-building complexes. Such lighting systemscommonly employ street-light fixtures, such as street-light fixtures102-104 in FIG. 1. Each street-light fixture includes a rigid, verticalpole 110 and arms or brackets 112, through which internal electricalwiring runs, that together support one or more lighting units 114. Eachlighting unit generally includes one or more lighting elements andassociated electrical ballasts that limit voltage drops across, andcurrent drawn by, lighting elements and that buffer voltage and/orcurrent surges and shape the input voltage or current in order toprovide a well-defined output voltage or current for driving thelighting elements. Many different types of lighting elements arecurrently used, including light-emitting-diode (“LED”) panels,inductive-lighting, or compact fluorescent, elements,high-pressure-sodium lighting elements, mercury-halide lightingelements, incandescent lighting elements, and other types of lightingelements. A series of lighting fixtures is often interconnected along acommon electrical path within a public-utility electrical grid. Lightingfixtures are often controlled by photocell switches 116, which respondto ambient illumination and/or lack of ambient illumination, to power onlighting elements during periods of darkness and power off lightingelements when adequate ambient daylight is available.

Even modestly sized industrial, commercial, educational, and otherfacilities often employ a large number of lighting fixtures for avariety of different purposes. FIG. 2 shows a modestly sized industrialor commercial site with associated lighting-fixture locations. Theindustrial site shown in FIG. 2 includes an administration building 202,an operations building 204, three laboratory buildings 206-208, andthree parking lots 210-212. The locations of lighting fixtures are shownas filled disks, such as filled disk 214. Certain of the lightingfixtures are located along roadways, such as lighting fixture 220, andmay serve to illuminate the roadways as well as illuminating portions ofbuildings adjacent to the roadways, building entrances, walkways, andother portions of the environment surrounding the buildings androadways. This type of lighting provides safety for operators of motorvehicles and pedestrians, and may address certain security concerns.Other lighting fixtures, including double-arm lighting fixtures 224-226,illuminate parking lots, and are employed primarily for the convenienceof parking-lot users as well as for security purposes. Other lightingfixtures, including the lighting fixtures that surround the laboratorybuildings 206-208, including lighting fixture 230, may serve primarilyfor facilitating security in and around high-security buildings andareas.

There are many problems associated with even simple lighting systems,such as those shown in FIGS. 1 and 2. Photocell control of lightingfixtures is relatively crude, providing 100 percent power to lightfixtures during periods of darkness and no power to light fixturesduring periods of adequate ambient light. Thus, lighting is controlledprimarily according to day length, rather than to the needs offacilities and people who work in, and travel through, the facilities.Photocells and photocell-control circuitry may fail, leading to lightingfixtures remaining constantly powered on, significantly shortening theuseful length of lighting elements and significantly increasing energyconsumption by lighting fixtures. As discussed with reference to FIG. 2,various different lighting fixtures within a facility may be used fordifferent purposes, and therefore could optimally be controlledaccording to different schedules and lighting-intensity requirements,were such control possible. However, current lighting systems generallylack effective means for differentially operating lighting fixtures andlighting elements within them. For these and many other reasons,manufacturers and vendors of lighting fixtures and lighting systems,organizations and agencies responsible for acquiring, operating,maintaining, and administering lighting systems, and ultimately all whoenjoy the benefits of lighting systems continue to seek improved systemsfor controlling lighting systems, so that lighting can be provided ascost effectively as possible to meet various different lighting needsand requirements.

As discussed above, current lighting systems, in which individuallighting fixtures are controlled generally by photocells, and in whichgroups of electrically interconnected lighting fixtures may beadditionally controlled at the circuit level by timers and other crudecontrol mechanisms, do not provide flexibility and precision of controlneeded to optimize control of lighting systems in order to provideneeded lighting intensities at particular times on anindividual-lighting-fixture basis, monitor lighting fixtures for output,component failure, and other operational characteristics, and providelocal-area-wide, regional, and larger-geographical-area-wide approachesto control of lighting systems. By contrast, embodiments of the presentinvention provide precise control of lighting fixtures, regardless ofelectrical-connection topologies, in local, regional, and larger areasthrough automated control systems, public communications networks,including the Internet, radio-frequency communications, and power-linecommunications. Embodiments or the present invention thus provide forflexible, scheduled, and controlled operation of lighting fixtures downto the granularity of individual lighting elements within individuallighting fixtures and up to arbitrarily designated groups of lightingfixtures that may include millions of lighting fixtures distributedacross large geographical areas. In addition, embodiments of the presentinvention provide for automated monitoring of lighting elements,lighting fixtures, and the environment surrounding lighting fixturesmade possible by flexible control of light-management units,lighting-fixture-embedded sensors, and bi-directional communicationsbetween light-management units, routers, and network-control centers.Embodiments of the present invention provide for control of activecomponents included in lighting fixtures, including automated activationof heating elements, failure-amelioration circuitry, and other suchlocal functionality by the hierarchical control systems that representembodiments of the present invention.

FIGS. 3A-B illustrates a conceptual approach to lighting-system controlthat represents one embodiment of the present invention. According tothis embodiment of the present invention, lighting-system control isimplemented hierarchically, with a top-level network-control center 302directly communicating with multiple routing devices 304-310, each ofwhich, in turn, communicates with one or more radio-frequency(“RF”)-enabled bridging lighting-fixture-management units (“LMUs”)320-331 within individual fixtures that control operation of thelighting fixtures and that, in turn, communicate with one or moreend-point LMUs within individual lighting fixtures via power-linecommunications. In general, the network-control center communicates withrouters via network communications, including the Internet. However,network-control centers may also employ cellular telephone networkcommunications, radio-frequency communications, and other types ofcommunications in addition to network communications, in alternativeembodiments. The routers intercommunicate with LMUs via radio-frequencycommunications, power-line communications, and, in alternate embodimentsof the present invention, using other types of communications. Incertain embodiments of the present invention, RF-enabled, bridging LMUsintercommunicate with routers using radio-frequency communications, andthe RF-enabled, bridging LMUs communicate with additional end-point LMUsvia power-line communications.

Each router, such as router 304, is associated with a number ofindividual lighting fixtures containing LMUs, such as the lightingfixtures within the region enclosed by dashed line 340 in FIG. 3, thatintercommunicate with the router to provide control of the lightingfixtures. The routers, in turn, communicate with a network-controlcenter 302 that provides for centralized, automated control of all ofthe lighting fixtures controlled by all of the routers that communicatewith the network-control center. In one embodiment of the presentinvention, there are four levels within the hierarchy of controllers:(1) the centralized network-control center 302; (2) a number of routinedevices 304-310; (3) RF-enabled bridging LMUs; and (4) additionalend-point LMUs that communicate with the RF-enabled bridging LMUs viapower-line communications. In alternative embodiments of the presentinvention, additional hierarchical levels may be included so that, forexample, multiple network-control centers may communicate with ahigher-level central control system for control of a very largegeographical region. Alternatively, multiple geographically separatednetwork-control centers may be implemented to intemperate as adistributed network-control center. Note that the lighting fixturescontrolled through a particular router, such as the lighting fixtureswithin the area surrounded by dashed curve 340, are not necessarilygeographically distinct from the lighting fixtures controlled by anotherrouter. The LMUs contained within individual lighting fixtures providepolicy-driven, individualized, automated control over each of one ormore lighting elements within the lighting fixture, provide for manualcontrol of lighting elements, receive and process data from sensors, andcontrol various active devices within lighting fixtures. Up to 1,000 ormore LMUs may communicate with, export data to, and receive policydirectives and data from, a particular routing device, and thenetwork-control center may communicate with, receiving data from, andexport policy directives to up to 1,000 or more routing devices. Thus,the network-control center may provide automated control of a million ormore individual lighting fixtures.

While embodiments of the present invention allow individual lightingelements within individual lighting fixtures to be manually controlledfrom user interlaces provided by routing devices and user interfacesprovided by the network-control center, manual control would be tediousand error prone. Automated lighting-control systems that representembodiments of the present invention provide the ability to logicallyaggregate individual lighting fixtures into various different groups oflighting fixtures for control purposes. FIG. 4 illustrates, using thesame exemplary industrial-site layout shown in FIG. 2, groupings ofindividual lighting fixtures to facilitate automated control, madepossible by lighting-control systems that represent embodiments of thepresent invention. As shown in FIG. 1, the various different lightingfixtures, represented by tilled disks, such as filled disk 220, arecombined into 11 different control groups. Lighting fixtures along apublic thoroughfare, including lighting fixture 220, are groupedtogether into a first group 402, labeled with the group number “1.”Lighting fixtures behind the administration building and operationsbuildings 202 and 204, along a smaller roadway 404 and a large parkinglot 212, are divided into two groups: (1) group 2 (406 in FIG. 4); and(2) group 3 (408 in FIG. 4). By partitioning these lighting fixturesinto two groups, alternate lights along the roadway and parking lot canbe activated on alternate days, lowering energy consumption andincreasing lighting-element operational lifetimes. Alternatively, all ofthese lighting elements could be combined in a single group, andoperated at lower light-intensity output in order to achieve similarpurposes. Similarly, the dual-arm lighting elements within parking lot212 are divided into two groups 410 and 412 so that lighting elements ononly a single arm of each dual-arm lighting fixtures are powered onduring a given day. Groups can be as small as individual lightingfixtures, such as groups 6 and 7 (420 and 422 in FIG. 4) or even assmall as individual lighting elements within lighting fixtures. Thehierarchical, automated control of lighting can be feasibly scaled,according to various embodiments of the present invention, to controlall of the lighting fixtures within an entire nation or continent. Thehierarchical implementation of the automated lighting control systemthat represents one embodiment of the present invention provides bothscalability and communications flexibility. As one example, FIG. 3Bshows a portion of a lighting-control system that uses a number ofdifferent types of communications methodologies. In FIG. 3B, a router350 manages LMUs within eight different lighting fixtures 352-359. Thelighting fixtures are partitioned into two different groups, including afirst group 352-355 serially interconnected by a first power line 360emitted from a transformer 362 and a second group 356-359 seriallyinterconnected by a second power line 364 emitted from the transformer362. Were both groups of lighting fixtures connected to a single powerline, without the transformer 362 separating the two groups of lightingfixtures, all of the LMUs within the lighting fixtures could directlycommunicate with the router using only power-line communications.However, power-line communications cannot bridge transformers 362 andvarious other electrical-grid components. It would be possible to usetwo routers, one for each group of lighting fixtures, and interconnecteach router to its respective group of lighting fixtures usingpower-line communications. However, a two-router implementation wouldinvolve connection and location constraints with regard to the routers,unnecessary duplication of router functionality, and higher cost.Instead, according to various embodiments of the present invention, therouter 350 communicates by radio-frequency communications withRF-enabled, bridging LMUs in each of lighting fixtures 354 and 358. EachRF-enabled, bridging LMU intercommunicates with the remaining lightingfixtures of the group of lighting fixtures in which the bridging LMU islocated using power-line communications. The bridging LMUs serve both asa local LMU within a lighting fixture as well as a communications bridgethrough which end-point LMUs in each group can receive messages from,and transmit messages to, the router 350. Thus, radio-frequencycommunications and RF-enabled, bridging LMUs provide a cost-effectiveand flexible method for bridging transformers and otherpower-line-communications-interrupting components of an electricalsystem. In addition, each LMU may include cell-phone-communicationscircuitry to allow the LMU to communicate directly with a cellulartelephone 370. A cellular telephone can act as a bridge to a router oras a specialized, local router, to enable maintenance personnel tomanually control an LMU during various monitoring and servicingactivities.

In certain embodiments of the present invention, LMUs control operationof lighting elements within lighting fixtures according tointernally-stored schedules. FIG. 5 illustrates a displayed schedule forautomated control of the various groups of lighting fixtures shown inFIG. 4 according to certain embodiments of the present invention.Schedules may be displayed, in various ways, by router andnetwork-control-center user-interface routines, allowing interactivedefinition, modification, and deletion of schedules by authorized users.As shown in FIG. 5, a schedule thr lighting-element operation within thelighting fixtures of each of the 11 groups shown in FIG. 4 is providedfor a particular day. Each horizontal bar, such as horizontal bar 502,represents the schedule for operation of lighting elements within thelighting fixtures of a particular group according to the time of day. Incertain embodiments of the present invention, entire lighting fixtures,including all lighting elements within the lighting fixtures, areassigned to groups, while in alternative embodiments of the presentinvention, individual lighting elements within lighting fixtures may beseparately assigned to groups. The time of day increments from 12:00a.m., at the left-hand edge of the horizontal bar 504, to 12:00 p.m. 506at the right-hand edge of the horizontal bar. Shaded regions within thehorizontal bar, such as shaded region 508 in horizontal bar 502,indicate times during which the lighting elements should be powered on.The heights of the shaded regions indicate the level to which thelighting element should be powered on. For example, shaded region 510 inhorizontal bar 1 indicates that the lighting elements within thelighting fixtures of group 1 should be powered on to 50 percent ofmaximum intensity between 12:00 a.m. and 2:00 a.m., while the right-handportion of shaded region 508 indicates that the lighting elements withinthe lighting fixtures within group 1 should be powered on to maximumintensity from 6:30 p.m. until midnight.

In addition, event-driven or sensor-driven operational characteristicscan be defined for each group. For example, in FIG. 5, small horizontalbars, such as horizontal bar 514, indicate how the lighting elementsshould be operated when various different events occur. For example,horizontal bar 514 indicates that, in the event that the photocelloutput transitions from on to off, indicating that the ambient lightinghas increased sufficiently to trip the photocell-signal-outputthreshold, the lights, when already powered on at or above 50% ofmaximum intensity, should be operated for an additional 15 minutes at 50percent of maximum light-intensity output, represented by shaded bar316, and then powered off. Operational characteristics can be specifiedfor the photocell-on event, indicating a transition from adequatelighting to darkness, and for an input signal from a motion sensorindicating motion within the area of a lighting fixture. Operationalcharacteristics for many additional events may be specified, as well asoperational characteristics for additional controllable devices andfunctionality, including heating elements activated to remove snow andice, various failure-recovery and fail-over systems, and other suchdevices and functionality.

There are many different approaches to specifying lighting-elementoperation and many different considerations for providing the differentoperational characteristics represented by the different horizontal barsfor each group shown in FIG. 5, which in turn represent encodedoperational schedules and event-related operational directives. Forexample, it would make no sense to power on lighting elements inresponse to a photocell-off event. The intent of the small shaded bar516 within horizontal bar 514 is that, had the lights been powered on togreater than 50 percent of maximum intensity, lighting elements shouldbe powered down to 50 percent of maximum intensity for a brief period oftime before being powered off entirely. Thus, a combination of thetime-incremented, large horizontal bar 502 and smaller horizontal bar514 may specify that, at any point in time, the light should be poweredon to the minimum power level indicated in the time-of-day schedule barand the shorter horizontal bar corresponding to the photocell-off event.However, in other cases, light may need to be powered on to the maximumpower level indicated in the time-of-day schedule bar and a different,shorter horizontal bar corresponding to a different type of event. Ingeneral, the ultimate operational characteristics of a light fixture,implemented by an LMU installed within the light fixture, may be definedby arbitrary Boolean and relational-operator expressions or shortinterpreted scripts or computer programs that compute, for anyparticular point in time, based on sensor input signals and on thestored time-based schedule and stored operational characteristicsassociated with particular events, the degree to which the lightingelement should be powered on.

FIG. 6 provides a generalized architecture for the automatedhierarchical lighting-control system that represents one embodiment ofthe present invention. Large-area control is exercised over manylighting fixtures within a large geographical area via automated controlprograms running within a network-control center 602. Thenetwork-control center includes, in addition to the control programs,one or more relational database management servers 603 or other types ofdata-storage systems and multiple web servers, or otherinterface-serving systems, 605-607 that together comprise a distributed,automated lighting-control-system network-control center. Thenetwork-control center web servers serve lighting-system-controlinformation to multiple routers 610-613 via the Internet 616 or viaradio-frequency transmitters 618. In addition, the network-controlcenter may provide a web-site-based network-control-center userinterface 620 via a personal computer or work station 622 interconnectedwith the network-control center by the Internet or a local area network.In certain embodiments of the present invention, the network-controlcenter may provide functionality similar to that provided by individualrouters, including the ability to monitor the state of individual LMUs,define groups, define and modify schedules, manually control lightingfixtures, and carry out other such tasks that can be carried out on alocal basis through the user interlace provided by a router. Inaddition, the network-control center may provide additionalfunctionality, not provided at the router level, includingcomputationally complex analysis programs that monitor and analyzevarious characteristics of lighting systems, including powerconsumption, maintainability, and other such characteristics, over verylarge geographical areas.

The routers may be implemented in software that runs on a laptop orpersonal computer, such as router 611, may be stand-alone devices, suchas routers 610 and 612, or may be stand-alone devices associated with apersonal computer or workstation on which stand-alone routers displayuser interfaces provided to users, as in the case of router 613 in FIG.6. Routers communicate with RF-enabled LMUs 630-640 via wirelesscommunications, including IEEE802.15 (Zigbee) communications, and theRF-enabled LMUs may both control a particular lighting fixture as wellas act as a bridge between additional end-point LMUs with which thebridge LMUs communicate via power-line communications, including EchelonPower Line (ANSI/EIA 709.1-A). In certain embodiments of the presentinvention, routers may communicate to LMUs via power-linecommunications, such as muter 612 and LMU 633 in FIG. 6. In stillfurther embodiments of the present invention, other types ofcommunications may be employed for communicating information betweennetwork-control centers and routers, between routers and bridge LMUs orend-point LMUs, and between bridge LMUs and end-point LMUs. Variousdifferent chip sets and circuitry can be added to LMUs, routers, andcomponents of network-control centers to enable additional types ofcommunications pathways.

Both bridge LMUs and end-point LMUs control operation of lightingelements within light fixtures and collect data through various types ofsensors installed in the light fixtures. Both types of LMUs controllighting-fixture operation autonomously, according to schedulesdownloaded into the LMUs from routers and network-control centers ordefault schedules installed at the time of manufacture, but may alsodirectly control operational characteristics of lighting fixtures inresponse to commands received from routers and network-control centers.The schedules and other control directives stored within LMUs may bemodified more or less arbitrarily by users interacting with userinterfaces provided by routers and network-control centers. While, inmany applications, the control functionality of the LMUs is asignificant portion of the automated lighting-system controlfunctionality provided by embodiments of the present invention, in manyother applications, monitoring functionality provided by LMUs is of asgreat a significance or greater significance. The LMUs architectureprovides for connecting numerous different sensor inputs to LMUs,including motion-sensor inputs, chemical-detection-sensor inputs,temperature-sensing inputs, barometric-pressure-sensing inputs, audioand video signal inputs, and many other types of sensor inputs inaddition to voltage and power sensors generally included in LMUs. TheLMUs response to each of the different types of input signals may beconfigured by users from user interlaces provided by routers andnetwork-control centers. The various types of sensor input may be usedprimarily for providing effective control of lighting-system operation,in certain cases, but also may be used for providing a very largevariety of different types of monitoring tasks, at local, regional, andlarge-geographical-area levels. LMU sensing can be employed, forexample, for security monitoring, for monitoring of traffic patterns anddetection of impending traffic congestion, for facilitating intelligentcontrol of traffic signals, for monitoring local and regionalmeteorological conditions, for detecting potentially hazardous events,including gunshots, explosions, release of toxic chemicals into theenvironment, tire, seismic events, and many other types of events,real-time monitoring of which can provide benefits to municipalities,local government, regional governments, and many other organizations.

FIG. 7 provides a block diagram for a radio-frequency-enabledlight-management unit according to one embodiment of the presentinvention. The RF-enabled LMU includes an RF antenna 702, a wirelesscommunications chip or chip set 704 that provides for wireless receptionand transmission of command and response packets, apower-line-communications chip or chip set 706 that provides orpower-line reception and transmission of command and response packets, anoise filter 707 that band-pass filters noise from the power-lineconnections, a CPU 708 and associated memories for running internalcontrol programs that collect and store data, that controllighting-element operation according to stored data and stored programs,and that provide forwarding of packets from RR to PL, communications andfrom PL to RF communications, an internal power supply that converts ACinput power to DC internal power for supplying DC power to digitalcomponents, an optocouple isolation unit 710 that isolates the CPU frompower surges, a dimming circuit 712 that provides digital pulse-widthmodulation of the electrical output to lighting elements to provide arange of output current for operating certain types or lighting elementsover a range of light-intensity output, a digital-to-analog circuit 714that provides controlled voltage output to lighting elements or othercomponents, and a switched relay 716 for controlling power supply tovarious devices or components within a lighting fixture, includingballasts.

FIG. 8 provides a block diagram for a stand-alone routing deviceaccording to one embodiment of the present invention. The stand-alonerouting device includes many of the same elements as included in theRF-enabled LMU, as shown in FIG. 7, with the addition of alocal-area-network communications controller and port 802 and othercommunications components 804 and 806 that allow the stand-alone routerto interconnect with a personal computer or workstation for display of auser interface.

FIG. 9 illustrates communications between routers,radio-frequency-enabled light-management units, and end-pointlight-management units according to one embodiment of the presentinvention. Both commands and responses are encoded in packets comprisingbetween seven and 56 bytes for RF communications. The RF communicationsprotocol is a command/response protocol that allows routers to issuecommands to RF-enabled LMUs and receive responses from those commandsand that allows RF-enabled LMUs to issue commands to routers and receiveresponses to those commands from the routers. Broadcast messages andone-way messages are also provided for. Each command or response packetincludes a six-byte ID 902, a single-byte command identifier or code904, and between zero and 49 bytes of data 906. The ID 902 is used toidentify particular LMU or RF-enabled LMUs from among the LMUs thatcommunicate with the router. The commands and responses are packagedwithin power-line-communications applications packets for communicationsvia power-line communications via the Echelon power-line communicationsprotocol.

FIG. 10 illustrates division of the 256 possible command codes into foursubsets, according to certain embodiments of the present invention. InFIG. 10, a central horizontal column 1002 includes the 256 differentpossible command codes that can be represented by the one-bytecommand-code field within the communications packets used both for RFcommunications and PL communications. The even-numbered command codescorrespond to commands, and the odd-numbered command codes correspond toresponses, with the response for a particular command having a numericvalue one greater than the numeric value of the command code for thatparticular command. Command codes and response codes forrouter-to-end-point-LMU commands have the lower-valued codes,represented as the code values above horizontal dashed line 1004.Router-to-bridge LMU commands have the higher-valued command codes,represented by the command codes below the horizontal dashed line 1004.Thus, a bridge LMU can immediately determine, from the command code,whether a command received from a router should be processed by thebridge LMU for local control of a light fixture or forwarded, via PLcommunications, to downstream LMUs. Similarly, theend-point-LMU-to-router commands have lower-numbered command codes andthe bridge-LMU-to-router commands have higher numerically valued commandcodes. Any particular command code, such as command code “0” 1006, maycorrespond to a router-to-LMU command or to an LMU-to-router command.The routers and LMUs can distinguish these different commands becausethe router receives only LMU-to-router commands and LMUs receive onlyrouter-to-LMU commands.

FIG. 11 shows the type of data stored within each light-management unitaccording to certain embodiments of the present invention. Each LMUstores information for each of up to a fixed number of lighting elements1102-1105, a number of group identifiers 1112 that identify groups towhich the LMU is assigned, various input/output device descriptors 1114,the status for each of various different events 1116, and a schedule1118 comprising up to some maximum number of operational directives.Each set of information describing a particular lighting element, suchas the information that describes lighting element “0” 1102, includes alamp-status 1120 with a hit indicating whether or not the lightingelement is powered on or off 1121 and a field indicating the degree towhich the light is powered on with respect to the maximumlight-intensity output of the light 1122. In addition, the total hoursof operation for the lighting element 1124, total operation of theballast associated with the lighting element 1126, and the number ofpower-on events associated with the lighting element 1128 are stored,along with various additional types of information, in particularembodiments of the present invention. Information regarding the lightfixture 1108 includes a current power consumption 1130, a current orinstantaneous voltage across the lighting fixture 1132, a current drawnby the lighting fixture 1134, an accumulated energy used by the lightingfixture 1136, flags that indicate whether particular alarms, othersensor inputs, or other input signals are active or inactive 1138, and aset of flags indicating whether or not particular relays and otheroutput components are active or inactive 1140. Lighting fixtureinformation also includes a cumulative light status 1142 that indicateswhether or not any of the light elements associated with the lightfixture are on or off. The status bits 1110 include a variety ofdifferent bit flags indicating various types of problems, includingoverride events, sensor failures, communications failures, absence ofstored data needed for control of light-element operation, and othersuch events and characteristics. The I/O device descriptors 114 providea description of the meaning of each of various input signals that canbe monitored by the LMU. Each operational directive within the schedule1118 includes an indication of the day 1150, start time 1152, end time1154, and lamp status 1156 associated with the directive, as well as agroup ID 1158 that indicates a group to which the directive applies.

FIGS. 12A-B illustrate data managed by a router for all of the differentlight-management units or light-fixtures which the router managesaccording to certain embodiments of the present invention. In FIGS.12A-B, a set of relational-database tables are provided to indicate thetypes of information maintained by a router regarding the LMUs managedby the router. Of course, any number of various different databaseschemas may be designed to store and manage information for routers inalternative embodiments of the present invention. The relational tablesshown in FIGS. 12A-B are intended to provide an exemplary databaseschema in order to illustrate the types of data stored within a router.The relational tables of the exemplary schema include: (1) ComponentType 1202, which lists the various types of components within alighting-control system, including internal components of lightingfixtures and lighting elements as well as LMUs, routers, and othercomponents; (2) Address 1204, which includes various different addressesreferenced from other tables; (3) Manufacturer 1206, which containsinformation about particular component manufacturers; (4) Maintainer1208, which contains information about various maintenance individualsor organizations responsible for maintaining components of the automatedlighting control system; (5) Administrator 1210, which containsinformation about various administrative organizations or individualadministrators that administrate portions of the lighting-controlsystem; (6) additional tables describing individuals or organizationsresponsible for supplying power, supplying, various other services, andother such individuals and organizations, not shown in FIGS. 12A-B; (7)Components 1212, which stores detailed information about particularcomponents within the lighting-control system; (8) Elec 1214, whichstores detailed electrical characteristics of particular systemcomponents, the rows of which are referenced from rows of the Componentstable; (9) Software 1216, which stores detailed software characteristicsof particular system components, the rows of which are referenced fromrows of the Components table; (10) Mechanical 1218, which storesdetailed mechanical characteristics of particular system components, therows of which are referenced from rows of the Components table; (11)Contains 1220, which stores pairs of component IDs that form therelationship “contains,” indicating the first component ID of the pairidentifies a component that contains the component identified by thesecond component ID of the pair; (12) Manages 1222, which stores a“manages” relationship between components; and (13) Groups 1224, whichcontains information about various groups of LMUs defined for therouter.

In the exemplary data schema shown in FIGS. 12A-B, the Component Typetable 1202 contains ID/description pairs that describe each of thedifferent types of components in the automated lighting system. The IDs,or identifiers, are used in the CT ID column of the Component table1212. The Address 1204. Manufacturer 1206. Maintainer 1208, andAdministrator 1210 tables include rows that provide descriptions ofaddresses, in the case of the Address table, and individuals ororganizations, in the case of the Manufacturer, Maintainer, andAdministrator tables. Each entry in the component table 1212 describes adifferent component within the automated lighting system. Each componentis identified by an identifier, or ID, in the first column 1230 of thecomponent table. Each component has a type, identified by thecomponent-type identifier included in the second column 1232. Eachcomponent has a manufacturer, identified by a manufacturer ID in thethird column 1234 of the Component table, where the manufacturer IDs aremanufacturer identifiers provided in the first column 1236 of theManufacturer table 1206. Components are additionally described bywarranty information, in columns 1240 and 1242, an installation date, incolumn 1244, a serial number, in column 1246, references to rows in theElec. Software, and other tables in columns 1248, 1250, and additionalcolumns not shown in FIG. 12A, and by a GPS location in column 1252.Many other types of information may be included in additional columnsthat describe components. The Elec table 1214 describes variouselectronic characteristics of a component, including the estimatedlifetime, in column 1254, an accumulated runtime for the component, incolumn 1256, the number of power-on events associated with thecomponent, in column 1258, and various thresholds, in columns 1260,1262, and additional columns not shown in FIG. 12B, for triggeringevents associated with a component. As one example, column 1260 includesa run-time alert that specifies that the lighting-control system shouldtake some action when the accumulated runtime hours are equal to orgreater than the threshold value shown in column 1260. The Software andMechanical tables 1216 and 1218 include various characteristics forsoftware components and mechanical components. Each group, in the Groupstable 1224, is described by an ID, in column 1270, a name, in column1272, various IDs far administrators, maintainers, and other serviceproviders associated with the group in columns 1274, 1276, andadditional columns not shown in FIG. 12B, the component ID or a routerassociated with a group, in column 1278, and the current schedules forthe group, in an unstructured column 1280.

Information stored in exemplary data schema shown in FIGS. 2A-B allowsfor responding to many different types of queries generated byuser-interface routines executed on a router or network data center. Forexample, if a user of the router-provided user interlace wishes to findall poles, or light fixtures, in the Supermall parking lot group, thefollowing SQL query can be executed by router user-interface routines toprovide serial numbers and GPS coordinates for the identified poles:

  Select GPS, SerialNo From Component C, ComponentType CT Where C.CTID =CT.ID AND  CT. Description = ‘pole’ AND  C.ID IN   (Select CID2 FromManages M1   Where M1.CID1 IN    (Select CID2 From Manages M2    WhereM2.CID1 IN     (Select RID From Groups G     Where G.Name = ‘SupermallPkg’     )    )   )

In certain embodiments of the present invention, a database storedlocally within the router or stored in a database management systemaccessible to the router via the network-control center mayautomatically trigger generation of messages sent from the router toLMUs when data is added or updated. In other embodiments of the presentinvention, the user interface routines may execute queries to update thedatabase, in response to user input through the user interface, and, atthe same time, generate commands for transmission to LMUs, whenappropriate. In certain cases, a separate, asynchronous router routinemay periodically compare the contents of the database to informationstored within the LMUs to ensure that the information content of theLMUs reflects the information stored within the database. In general,the information stored within the LMUs, including status, run-timecharacteristics, definitions of sensors, and other such information, isalso stored in the database of the router.

Routers exercise control over LMUs through a command interface. FIG. 13shows various commands used in router-to-light-management-unitcommunications according to certain embodiments of the presentinvention. These commands include: (1) the set-time command, which setsthe time stored with an LMU; (2) the define-groups command, which setsentries in the list of groups (1112 in FIG. 11) to which an LMU belongs;(3) the define-schedule command, which is used to define schedulesstored within LMUs; (4) the define-input/output command, which definesthe various sensor devices and associated events within LMUs; (5) theforce-lamp-state command, which provides for manual operation of alighting unit via the by a user interacting with the router through theuser interface or, in alternative embodiments, by a user interactingwith a cell phone; (6) the report-status command, which solicits statusinformation by the router from LMUs; (7) the report-status-commandreply, several forms of which are used to respond to report-statuscommands received by LMUs; (8) the event command, which reports eventsand which can be sent by any unit; (9) the set-operating-hours command,which allows the router to set various electrical characteristics forcomponents within a lighting fixture maintained by an LMU; (10) thedefine-lamp-characteristics command, which allows the router to storeparticular lamp characteristics for lighting elements within the LMUthat manages those lighting elements; (11) the firmware-update command,which prepares an LMU for reception of a firmware update; (12) thebackdoor command, a debugging command used to obtain data from LMU; and(13) the add remove command, which informs a bridging LMU of theaddition or deletion of an end-point LAM from the bridging LMUspower-line network. FIGS. 14A-N show the data contents of the variouscommands and replies discussed above with reference to FIG. 13. Thetables describing data fields of messages, provided in FIGS. 14A-N, areself-explanatory, and are not discussed further.

FIGS. 15-18 provide flow-control diagrams for the control functionalitywith a light-management unit according to one embodiment of the presentinvention. FIG. 15 provides a control-flow diagram for an LMU eventhandler, which responds to events that arise within an LMU. The eventhandler waits for a next event to occur, in step 1502, and thendetermines which event has occurred, and responds to the event, in theset of conditional statements, such as conditional statement 1504, thatfollow the wait step 1502. The event handler runs continuously withinthe LMU. When an asynchronous sensor event has occurred, such as theoutput signal from a photocell transitioning from on to off or from offto on, as determined in step 1504, then the event descriptor for theevent is found in the table of events (1116 in FIG. 11) and updated.When a timer has expired indicating that it is time to check the variousevents for which event descriptors are supplied in the list of events(1116 in FIG. 11), a check-events routine is called, in step 1508. Whenthe event corresponds to queuing of an incoming message to an incomingmessage queue, as determined in step 1510, then aprocess-received-commands routine is called in step 1512. When the eventcorresponds to queuing of an outgoing message to an outgoing-messagequeue, as determined in step 1514, then a process-outgoing-commandsroutine is called in step 1518. When the event represents expiration ofa timer controlling periodic checking of the stored operationalschedule, as determined in step 1520, then a check-schedule routine iscalled in step 1522. Any of various other events that may occur arehandled by a default event handler, evoked in step 1524. The eventsexplicitly handled in FIG. 15 are merely a set of exemplary events, usedto illustrate overall functionality of the LMU event handler.

FIG. 16 provides a control-flow diagram oldie check-events routine,called in step 1508 of FIG. 15. In the for-loop of steps 1602-1608, eachevent descriptor in the list of event descriptors (1116 in FIG. 11)within an LMU is considered. If the event is described as being active,or having more recently occurred than handled, then, in general, amessage reporting the event is queued to an outgoing message queue, instep 1604, and, when local action is warranted, as determined in step1605, the event is handled locally in step 1606. Following messagequeuing and local handling, the event status is reset, in step 1607.Other types of evens may be reported, but not handled locally. Othertypes of events may both be reported to the router as well as handledlocally. For example, a temperature-sensor event may elicit localactivation or deactivation of a heating element in order to locallycontrol temperature.

FIG. 17 provides a control-flow diagram of the routine “process receivedcommands” called in step 1512 of FIG. 15. The next command is dequeuedfrom an incoming command queue in step 1702. When the command is aretrieve-information command, as determined in step 1704, then theappropriate information is retrieved from the information stored by theLMU and included in a response message that is queued to anoutgoing-message queue, in step 1706. A queue-not-empty event is raised,in step 1708, upon, queuing the message to the outgoing message queue.When the command is a store-information command, as determined in step1708, then information received in the command is stored into theappropriate data structure within the LMU, in step 1710. When anacknowledgement is needed, as determined in step 1712, then anacknowledgement message is prepared, in step 1714, and queued to theoutgoing message queue. When the command elicits local action, asdetermined in step 1716, then the local action is carried out in step1718 and, when an acknowledgment message is required, as determined instep 1720, the acknowledgement message is prepared and queued in step1714. When the command queue is empty, as determined in step 1722, thenthe routine ends. Otherwise, control returns to step 1702 for dequeuingthe next received command.

FIG. 18 provides a control-flow diagram for the routine “checkschedule.” called in step 1522 of FIG. 15. In the for-loop of steps1802-1810, each entry in the schedule (1118 in FIG. 11) stored locallywithin the LMU is considered. Current time is compared to the start-timeand end-time entries of the currently considered schedule, in step 1803.When the current time is within the range specified by the start-timeand end-time entries of the currently considered schedule event orentry, then, in the inner for-loop of steps 1805-1809, each lightingelement within the light fixture controlled by the LMU is considered.When the currently considered lighting element is within the group forwhich the schedule entry is valid, as determined by comparing the groupID of the schedule entry with the group ID of the lighting element, thenwhen the current lighting-element output is different from thatspecified by the schedule, then, in step 1808, the LMU changes theoutput of the lighting element to that specified in the schedule byaltering the voltage or current output to the lighting element.

FIG. 19 provides a state-transition diagram for one router userinterface that represents one embodiment of the present invention. Whena user interacts through a user interface with a router, the routerinitially displays a home page 1902. The user may wish to view data,update and modify data, or manually control one or more LMUs and, incertain embodiments of the present invention, may select one of thesethree types of interactions and undergo authorization in order to carryout these types of actions through one or more authorization pages1904-1906. Users may be required to provide passwords, pass fingers overfingerprint identifiers, provide other information that authorizes theuser to carry out these and other types of tasks by interacting with theuser interface. Various sets of web pages may allow a user to view ormodify groups defined for LMUs and the association of LMUs with groups,calendar-like schedule of desired lighting operation, informationregarding lighting fixtures and components contained within lightingfixtures, and information regarding, fixture locations, including theability to view fixture locations overlaid onto maps or photographicimages of the area within which the LMUs are contained. There are alarge number of different possible user interfaces that can be devisedto provide interactive control of LMUs and lighting fixtures managed bya particular router. Similar user interfaces may be provided at thenetwork-control center level.

FIGS. 20-26 provide additional description of theradio-frequency-enabled light-management unit (“RF-Enabled LMU”)discussed above with reference to FIG. 7. FIG. 20 shows a block diagramfor the RF-enabled LMU that represents one embodiment of the presentinvention, similar to the block diagram shown in FIG. 7, with additionaldetail and with dashed-line indications of subcomponents, circuitdiagrams for which are provided in FIGS. 21-26. The circuit diagramsprovided in FIGS. 21-26 include addition description of the followingsubcomponents, indicated by dashed-line rectangles in FIG. 20: (1) themicroprocessor 2002; (2) the optocouple-isolation subcomponent 2004; (3)the switched-relay subcomponent 2006; (4) the internal-power-supplysubcomponent 2008; and (5) a power-meter subcomponent 2010. Thepower-meter component 2010 is an integrated-circuit-implemented powermeter that monitors power usage of the luminaire or luminaires thatreceive electrical power through the AC power lines 2012-2013. Softwareroutines within the RF-enabled LMU query the power-meter component 2010,generally at regular intervals in time and/or upon requests receivedfrom a router or network control center, in order to monitor power usageby the luminaire or luminaires managed by the RF-enabled LMU and reportthe power usage back to the router or network-control centers.

FIG. 21 provides additional description of the microprocessor component(2002 in FIG. 20) of the RF-enabled LMU that represents one embodimentof the present invention. The microprocessor 2102 includes a largenumber of pins, to which external signal lines are coupled, that providean interlace between the microprocessor and other RF-enabled-LMUcomponents. In FIG. 21, the pins are numerically labeled from 1 to 32.Interrupt-like signals 2104-2105 are input to pins 12 and 13 by varioussensor or monitor components of the RF-enabled LMU. The microprocessoroutputs a relay signal 2106 to the switched-relay component (2006 inFIG. 20) to disconnect the luminaire from the AC power source. Themicroprocessor receives a signal 2108 from a thermistor temperaturesensor in order to monitor the temperature within the light-fixturehousing in which the RF-enabled LMU resides. A group of signals 2110provide a universal-asynchronous-receiver-transmitter (“UART”) interfaceto the wireless module (704 in FIG. 7) and another group of signal lines2112 provides an interlace to the power-line communications module (706in FIG. 7). Signal lines 2114-2115 provide a clock input to themicroprocessor and the group of signal lines 2116 implements aserial-peripheral-interface (“SPI”) bus interface to the power-metercomponent (2010 in FIG. 20). Another group of signal lines 2118implements a pulse-width-modulation output. Several pins connect themicroprocessor to internal DC power 2120 and to ground 2122. Themicroprocessor 2102 includes flash memory for storing software programsthat implement control and communications functionalities of theRF-enabled LMU, as well as traditional processor subcomponents,including registers, arithmetic and logic units, and other suchsubcomponents. Any of a variety of different microprocessors may beemployed in RF-enabled LMUs that represent embodiments of the presentinvention.

FIG. 22 provides a circuit diagram for a portion of theoptocouple-isolation subcomponent (2004 in FIG. 20) of the RF-enabledLMU that represents one embodiment of the present invention. Input andoutput lines are electronically isolated from one another by an opticalconnection 2202 in which electronic signals are converted to lightsignals and the light signals converted back to electronic signals by alight-emitting diode (“LED”) and photodiode, respectively.

FIG. 23 provides a circuit diagram for one embodiment of theswitched-relay component (2006 in FIG. 20) of the RF-enabled LMU thatrepresents one embodiment of the present invention. When the relaysignal 2302 is deasserted, a solenoid switch or solenoid-switch-likedevice 2304 conductively interconnects input AC power to output ACpower. However, when the relay signal 2302 is asserted by themicroprocessor (2102 in FIG. 21), the solenoid decouples the input ACpower lines from output AC power lines, thus disconnecting the luminairefrom the main input power lines. When the microprocessor is notfunctioning, and prior to assertion of control over a light fixture bythe microprocessor and microprocessor-resident software control programswithin the RF-enabled LMU, the luminaire is connected to the AC-inputmain power lines, as a default state. Thus, prior to initialization ofthe microprocessor and control programs, and whenever the microprocessorand/or control programs fail to actively control the components of thelight fixture, the luminaire is directly connected to the main powerlines. As discussed above, the luminaire may be disconnected from themain power lines tinder RF-enabled LMU control as a result of commandsreceived from a router or network-control center.

FIG. 24 provides a circuit diagram for the internal-power-supplycomponent (2008 in FIG. 20) of the RF-enabled LMU that represents oneembodiment of the present invention. Input AC power 2402-2403 isrectified and stepped down, by a rectifier and transformer 2404 toproduce five-volt internal DC output 2406. The output power signal isstabilized by stabilization circuitry and components, including,capacitor 2408.

FIG. 25 provides a circuit diagram for the power-meter component (2010in FIG. 20) of an RF-enabled LMU that represents one embodiment of thepresent invention. The power meter is implemented as an integratedcircuit 2502 that interlaces to the microprocessor via the SPI businterface 2504 discussed above with reference to FIG. 21.

FIG. 26 provides a circuit diagram for a circuit that interconnectsoutput from a sensor or monitor device 2602 to an interrupt-like input2604 to the microprocessor according to one embodiment of the presentinvention. The output signal 2604 is asserted when the voltage dropacross sensor-output signal lines is greater than a threshold value.

For many reasons, light-emitting-diode (“LED”) based area lighting,including street lighting, is rapidly becoming a preferred lightingtechnology in many applications, including street-lighting applications.LED-based luminaires provide significantly greater energy efficiencythan incandescent bulbs, fluorescent lighting elements, and otherlighting element technologies. LED-based luminaires can be implementedand controlled to produce output light with desired spectralcharacteristics, unlike many other types of lighting elements, whichoutput light of particular wavelengths or wavelength ranges. LED-basedluminaires can be quickly powered on and off, and achieve fullbrightness in time periods on the order of microseconds. The output fromLED-based luminaires can be easily controlled by pulse-width modulationor by controlling the current input to the LED-based luminaire, allowingfor precise dimming. LED-based luminaires tend to tail over time, ratherthan abruptly tailing, as do incandescent or fluorescent lightingelements. LED-based luminaires have lifetimes that are longer than thelifetimes of other types of lighting elements by factors of between 2and 10 or more. LED-based luminaires are generally more robust thanother types of lighting elements, being far more resistant to shock andother types of mechanical insults. For these and other reasons,LED-based luminaires are predicted to largely replace other types oflighting elements in street-lighting applications during the next liveto ten years.

However, despite their many advantages. LED-based luminaires havecertain disadvantages, including a non-linear current-to-voltageresponse that requires careful regulation of voltage and currentsupplied to LED-based luminaires. In addition, LED-based luminaires arerelatively temperature sensitive. For these and other reasons.RF-enabled-LMU control of LED-based luminaires may provide even greateradvantages for LED-based lighting than for traditional types oflighting. For example. RF-enabled LMUs that represent embodiments of thepresent invention may include power meters and output-lumen sensors tofacilitate automated monitoring of LED-based-luminaire output in orderto determine when LED-based luminaires need to be replaced. In the caseof traditional types of lighting elements, which abruptly fail, isrelatively easy for maintenance personnel to identify failed lightingelements. By contrast, since LED-based luminaires fail gradually,monitoring by RF-enabled LMUs that represent embodiments of the presentinvention can provide a far more reliable, automated system formonitoring and detecting failing LED-based luminaires than monitoring bymaintenance personnel. In addition, the RF-enabled LMUs that representembodiments of the present invention can monitor temperature withinlighting fixtures at relatively frequent intervals and can automaticallylower power output to luminaires and take other ameliorative steps toensure that the temperature-sensitive LED-based luminaires remain withinan optimal temperature range.

FIG. 27-29 illustrate characteristics of LED-based lighting elements.FIG. 27 shows a typical, small LED lighting device. The LED light sourceis a relatively small chip of semiconducting material 2702 across whicha voltage dropped by a potential applied to the lighting device viaanode 2704 and cathode 2706 elements. Typically, a semiconducting chip2702 is mounted within a reflective cavity 2705 to direct light outward,in directions representing a solid angle defined by the reflectivecavity. In higher-power LEDs, the semiconductor chip is of significantlygreater size and generally mounted to a metal substrate to provide forgreater heat removal from the larger semiconductor chip.

FIG. 28 illustrates a principal of LED operation. A semiconductorcrystal that forms the light-emitting element of an LED device 28-2 isdifferentially doped to produce a p-n junction 2804. The p side of thecrystal contains an excess of positive charge carriers, or holes, suchas hole 2806, and the n side of the semiconductor contains an excess ofnegative charge carriers, or electrons, such as election 2808. At theinterface 2804 between the p and n portion of the semiconductor crystal,a shallow barrier region 2810 is formed in which electrons diffuse fromthe n side to the p side and holes diffuse from the p side to the nside. This harrier region represents a small potential-energy barrier tocurrent flow. However, when a voltage is applied 2812 across thesemiconductor in a forward direction, as shown in FIG. 28, referred toas “forward biasing.” the harrier is easily overcome, and current flowsacross the p-n junction. Reversing the polarity of the voltage source,referred to as “reverse biasing,” can induce current to flow through thesemiconductor in the opposite direction, although, when reverse currentflow is allowed to increase past a threshold reverse current, sufficientheat is generated to disrupt the semiconductor lattice and permanentlydisable the device. Asymmetrically doped semiconductor crystals, whichimplement p-n junctions, comprise the basic functional unit of manycomponents of modern electronic systems, including diodes, transistors,and other components. In the case of a light-emitting diode (“LED”),when the semiconductor chip is forward biased, and current flows acrossthe p-n junction, excited electrons combine with holes in a process bywhich the electrons transition to lower energy levels by releasing lightof a specific wavelength.

FIG. 29 shows a current-versus-voltage curve for a typical LED. When 0 Vis applied across the LED 2902, no current passes through the LED.Forward biasing of the LED produces a small initial current whichincreases exponentially past a threshold forward-biasing voltage 2904.Reverse biasing of the LED produces an exponential increase in reversecurrent flow past a breakdown-voltage threshold 2406. The LED emitslights that when an applied forward-biasing voltage exceeds thethreshold voltage 2420 in FIG. 29. However, the operationalapplied-voltage range within which light is emitted without sufficientcurrent flow to destroy the semiconductor lattice is quite narrow. Inother words, as shown in FIG. 29, a LED exhibits a high degree ofnon-linearity in current flow with respect to applied voltage, and evensmall increases in applied voltage in the exponential regions of thecurrent-versus-voltage curve can induce sufficient current flow withinthe device to destroy the device. For this reason, unlike inincandescent and fluorescent light elements, control of voltage orcurrent output to an LED-based luminaire needs to be relatively precise.LED-based area lighting fixtures generally employ LED driver componentsthat rectify input AC power and that output either constant-voltage orconstant-current DC power to the luminaire.

FIG. 30 illustrates a LED-based street-light luminaire. The LED-basedstreet-light luminaire 3002, shown inverted from normal installationorientation, includes a transparent cover 3004 through which lightemitted by LED elements, such as LED element 3006, in an array of LEDelements 3008 passes to illuminate an area. The LED-based street-lightluminaire includes a generally metallic housing 3010 with multiplefin-like projections, such as fin 3012, to facilitate heat removal fromthe LED array. The LED-based street-light luminaire may also include anLED driver that acts as a constant-voltage or constant-current powersource for the LED array. Input power and signal lines run through acollar-like fixture 3014 that also serves as a mechanical couple to alight-fixture bracket. In alternative types of LED-based street-lightluminaires, the LED driver may instead be placed within a component of alight fixture other than the luminaire housing, shown in FIG. 30, andinterconnected to the LED array by wiring threaded through thecollar-like fixture.

Many types of LED drivers are commercially available. One popular LEDdriver, used in certain street-light applications, outputs a constantcurrent of 0.70 A from input voltages of between 100V and 277V. The LEDdriver includes thermal-protection circuitry and tolerates sustainedopen-circuit and short-circuit events in the LED array. The LED driveris housed within a long, rectangular enclosure weighting under threepounds and with dimensions of approximately 21×59×37 centimeters.

FIGS. 31-33 illustrate one type of constant-output-current LED lampdriver. FIG. 31 shows the LED-lamp-driver. The LED-lamp-driver drives astring, or series, of LEDs 3102 based on input AC power 3104 using afixed-frequency pulse-width modulation controller integrated circuit3106. FIG. 32 provides a functional block diagram for the integratedcircuit (3106 in FIG. 31) of the Led-lamp driver. FIG. 33 provides afunctional circuit diagram for the integrated circuit (3116 in FIG. 31)within the LED-lamp driver.

FIG. 34 illustrates an RF-enabled LMU/LED-based-luminaire-driver modulethat represents one embodiment of the present invention. As shown inFIG. 34, the RF-enabled-LMU/LED-base-luminaire driver 3402 includes theRF-enabled LMU components 702, 704, 708, 710, 707, 709, and 716discussed above with reference to FIG. 7 as well as an additionalswitched relay 3406, LED-driver output subcomponent 3408, and a LEDdriver 3410 that rectifies and stabilizes input AC power to produce aconstant-current DC output to an LED array 3412. The additional switchrelay 3406 is controlled in identical fashion as the switched relay 716to ensure that, in a default mode prior to initialization of theRF-enabled LMU software or during periods of time in which theRF-enabled LMU is not actively controlling the light fixture, the LEDdriver is provided with input signals, in addition to input AC power, todrive light output from the LED array.

A problem that is addressed by a LED-driver-enhanced RF-enabled LMU thatrepresents one embodiment of the present invention is that the powerfactor for a LED-driver coupled to one or more luminaires is generallynot 1.0, as would be desired for maximum light output for minimumcurrent drawn from the main, but generally significantly less than one.When the power factor is 1.0, the waveform of the voltage matches thatof the current within the load, and the apparent power, computed as theproduct of the voltage drop across the load and current that passesthrough the load, is equal to the power consumed within the load andultimately dissipated to the environment as heat, referred to as thereal power. Linear loads with only net resistive characteristicsgenerally have a power factor of 1.0. By contrast, linear loads withreactive characteristics, due to capacitance or inductance in the load,store a certain amount of energy and release the stored energy hack tothe main during each AC cycle. Therefore the apparent power provided tothe load exceeds the real power consumed by the load. Non-linear loads,including rectifiers and pulse-width-modulation-based dimming circuits,change the voltage and current waveforms in complex ways, and may resultin power factors significantly below 1.0. LED-drivers include bothrectifiers and pulse-width-modulation-based dimming circuits, andtherefore represent non-linear loads that have power factorssignificantly below 1.0.

The problem with a power factor below unity is that more current isdrawn by the load from the main power supplier than is actually used togenerate power within the load. Although the excess current is not usedin the load, and is returned to the power supplier through the main, thehigher currents drawn by the load result in higher power losses duringtransmission, as a result of which power suppliers often charge higherrates for supplying power to devices with low power factors. Thus, formaximum cost and energy efficiency, the LED driver incorporated into aLED-driver-enhanced RF-enabled LMU needs additional circuitry andcircuit elements to increase the power factor of the LED-driver-enhancedRF-enabled LMU and LED-driver-enhancedRF-enabled-LMU-controlled-luminaires to a value as close to 1.0 aspossible. The power factor of reactive, linear loads can also beincreased by offsetting inductance in the load with added capacitance oroffsetting capacitance in the load with added capacitance inductance,referred to as “passive power factor correction.” The power factor ofnon-linear loads can be increased by using active circuit components,including boost converters, buck converters, or boost-buck converters,referred to as “active power factor correction.” Depending on theparticular implementation of the LED driver included in aLED-driver-enhanced RF-enabled LMU, the LED-driver-enhanced RF-enabledLMU needs additional active-power-factor-correction components, and, incertain cases, may also employ additionalpassive-power-factor-correction components. In general, loads with powerfactors of between 0.95 and 1.0 are not subjected to higher fees bypower suppliers, and thus the LED-driver-enhanced RF-enabled LMUs thatrepresent embodiments of the present invention are desired to have powerfactors in excess that equal or exceed 0.95. And additional problem withLED drivers is that the power factor may decrease when dimming circuitryis active, due to pulse-width modulation that introduces additionalharmonies into the voltage/current waveform. Thus, preferredLED-driver-enhanced RF-enabled LMUs that represent embodiments of thepresent invention include dynamic power-factor correction that canadjust to and correct dynamically the changing power factor of theLED-driver and coupled luminaires as the level of luminaire dimmingchanges.

Incorporation of an LED driver into the RF-enabled LMU provides aone-component solution for control of LED-based luminaires. For manyreasons, the types of centralized monitoring and control of lightfixtures made possible by RF-enabled LMUs that represent embodiments ofthe present invention are of particular need in LED-based street-lightfixtures. LED drivers and LED-based luminaires have narrow operationalparameter ranges, including narrow operational temperature ranges andrelatively strict requirements for input voltage and input current dueto the non-linearity of LED lighting elements. While certain types oftemperature monitoring and control circuitry can be included in LEDdrivers. RF-enabled LMUs provide a second level of centralized, remotemonitoring of operational parameters and both local and remote controlover lighting fixture to minimize and/or eliminate occurrences ofLED-driver-damaging and LED-array-damaging conditions. As discussedabove. RF-enabled LMU control can provide for precise monitoring ofpower consumption and light output by LED-based luminaires in order todetermine automatically and remotely the points in time at whichluminaires need to be serviced and replaced. Furthermore, integratingthe RF-enabled-LMU and LED-features together in a single modulesimplifies the design and manufacture of light-fixture components andreduces the cost of light fixtures.

Although the present invention has been described in terms of particularembodiments, it is not intended that the invention be limited to theseembodiments. Modifications will be apparent to those skilled in the art.For example, a variety of different hardware configurations and designsmay be used to implement end-point LMUs, bridge LMUs, routers, andnetwork-control centers. As discussed above, many of various differentcommunications methodologies can be employed for communications betweenhierarchical levels of components in a lighting-control system,according to embodiments of the present invention, by introducing properchip sets, circuitry, and logic support within network-control-centerhardware, router hardware, and LMU hardware. As discussed above, LMUscan be configured to accommodate many different types of sensor devicesand to control many types of local electronic and electromechanicaldevices, such as heating elements, motors that control video cameras,and other such devices and components. Software and logic components ofLMUs, routers, and network-control centers may be implemented in manydifferent ways by varying any of the many different implementationparameters, including programming language, operating system platforms,control structures, data structures, modular organization, and othersuch parameters. Router and network-control-center user interfaces maybe devised to provide many different types of automated lighting-systemcontrol and monitoring functionality. Lighting-fixture operation can becontrolled by schedules, by specifying operational characteristics thatfollow particular events, can be controlled manually throughmanual-control user interfaces, and can be programmatically controlledin each of the different levels within the hierarchical automatedlighting-system control systems that represent embodiments of thepresent invention, including relatively autonomous, programmatic controlby individual LMUs.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the invention.However, it will be apparent to one skilled in the art that the specificdetails are not required in order to practice the invention. Theforegoing descriptions of specific embodiments of the present inventionare presented for purpose of illustration and description. They are notintended to be exhaustive or to limit the invention to the precise formsdisclosed. Many modifications and variations are possible in view of theabove teachings. The embodiments are shown and described in order tobest explain the principles of the invention and its practicalapplications, to thereby enable others skilled in the art to bestutilize the invention and various embodiments with various modificationsas are suited to the particular use contemplated.

It is intended that the scope of the invention be defined by thefollowing claims and their equivalents:
 1. A lighting-control systemcomprising: two or more lighting fixtures, each containing one or morelight-emitting-diode-based lighting elements; two or morelighting-fixture management units, each of the lighting fixturesincluding a lighting-fixture management unit, each lighting-fixturemanagement unit including a light-emitting-diode-based-luminaire driverand storing control information and status information and controllingthe intensity of light emitted by the light-emitting-diode-basedlighting elements, over a range of intensities, within thelighting-fixture that contains the lighting-fixture management unitaccording to the stored control information; and a router that providesa user interface for creation and modification of operational schedulesfor automated control of the light-emitting-diode-based lightingelements within the lighting fixtures and that communicates withlighting-fixture management units, using a first communications mediumbetween the router and at least one lighting-fixture management unit andadditionally by an inter-lighting-fixture-management-unit communicationsmedium, in order to transmit control information to the lighting-fixturemanagement units and receive status information from thelighting-fixture management units; wherein lighting-fixture managementunits include bridge lighting-fixture management units and end-pointlighting-fixture management units; wherein each end-pointlighting-fixture management unit controls intensity of light emissionfrom light-emitting-diode-based lighting elements within the lightingfixture that contains the end-point lighting-fixture management unit,according to an operational schedule and additional control directivesstored within the end-point lighting-fixture management unit; whereineach end-point lighting-fixture management unit monitors input from oneor more sensors and generates events, based on sensor input; and whereineach end-point lighting-fixture management unit collects and storesstatus information related to operation of components within thelighting fixture that contains the end-point lighting-fixture managementunit.
 2. The lighting-control system of claim 1 wherein one or moreend-point lighting-fixture management units communicate with the routerdirectly by power-line communications.
 3. The lighting-control system ofclaim 1 wherein one or more end-point lighting-fixture management unitscommunicate with the router directly by radio-frequency communications.4. The lighting-control system of claim 1 wherein one or more end-pointlighting-fixture management units communicate with the router indirectlythrough power-line communications to a bridge lighting-fixturemanagement unit.
 5. The lighting-control system of claim 1 wherein eachbridge lighting-fixture management unit controls intensity of lightemission from light-emitting-diode-based lighting elements within thelighting fixture that contains the bridge lighting-fixture managementunit, according to an operational schedule and additional controldirectives stored within the bridge lighting-fixture management unit;wherein each bridge lighting-fixture management unit monitors input fromone or more sensors and generates events, based on sensor input; whereineach bridge lighting-fixture management unit collects and stores statusinformation related to operation of components within the lightingfixture that contains the bridge lighting-fixture management unit; andwherein each bridge lighting-fixture management unit receives commandsfrom the router for an end-point lighting-fixture management unitthrough the first communications medium and forwards the commands to theend-point lighting-fixture management unit by theinter-lighting-fixture-management-unit communications medium.
 6. Thelighting-control system of claim 1 wherein each lighting-fixturemanagement unit stores status information related to operation ofcomponents within the lighting fixture that contains thelighting-fixture management unit that includes: current voltage input tothe lighting fixture; current drawn by the lighting fixture; powerconsumed by the lighting fixture over an interval of time; indicationsof the occurrences of events indicated by sensor inputs; total hours ofoperation of light-emitting-diode-based lighting elements; and number ofpower-on events associated with light-emitting-diode-based lightingelements.
 7. The lighting-control system of claim 1 wherein eachlighting-fixture management unit comprises:inter-lighting-fixture-management-unit communications medium chip orchip set that provides for power-line reception and transmission ofcommand and response packets; a noise filter that band-pass filtersnoise from a power-line connection, a CPU and associated memories forrunning internal control programs that collect and store data, thatcontrol lighting-element operation according to stored data and storedprograms; an internal power supply that converts AC input power to DCinternal power for supplying DC power to digital components, anoptocouple isolation unit that isolates the CPU from power surges; thelight-emitting-diode-based-luminaire driver that controls voltage andcurrent output to the light-emitting-diode-based lighting elements toprovide a range of output current for operatinglight-emitting-diode-based lighting elements over a range oflight-intensity output; a switched relay for controlling AC power supplyto various devices or components within the lighting fixture thatcontains the lighting-fixture management unit; a switched relay forcontrolling DC power supply to various devices or components within thelighting fixture that contains the lighting-fixture management unit; andan integrated-circuit power meter.
 8. The lighting-control system ofclaim 1 wherein each lighting-fixture management unit stores datastructures, in a memory component, that contain entries which represent:an operational status of one or more light-emitting-diode-based lightingelements; one or more group identifiers that identify groups to whichthe lighting-fixture management unit is assigned; one or more inputsignals that can be monitored by the lighting-fixture management unit; astatus for each of one or more different events; and a schedule thatincludes one or more operational directives.
 9. The lighting-controlsystem of claim 1 wherein the first communications medium is aradio-frequency communications medium and wherein theinter-lighting-fixture-management-unit communications medium is apower-line communications medium.
 10. The lighting-control system ofclaim 9 wherein the router additionally communicates with remotecomputers by network communications, wherein the router additionallycommunicates with lighting-fixture management units by power-linecommunications, and wherein both the router and one or morelighting-fixture management units communicate with hand-heldtelecommunications devices using cellular-telephone communications. 11.The lighting-control system of claim 1 further including one or moreadditional routers that each communicates with one or more additionallighting-fixture management units.
 12. The lighting-control system ofclaim 11 further including a network-control center that communicates,through network communications, with, and controls operation of, therouters.
 13. The lighting-control system of claim 1 wherein thelighting-fixture management units include sensor components that monitorone or more of: current; voltage; sound; camera data; volatile chemicalsubstances; power consumption by lighting-fixture components;temperature; and pressure.